Great Plains grassland methane dynamics

The grassland biome is an important sink for CH4, a major greenhouse gas. There is considerable uncertainty in the grassland CH4 sink capacity due to diverse environmental gradients in which grasslands occur, and many environmental conditions can affect abiotic (e.g., CH4 diffusivity into soils) and biotic (e.g., methanotrophy) factors that determine spatial and temporal CH4 dynamics. We investigated the relative importance of a soil’s gas diffusivity vs. net methanotroph activity in 22 field plots in seven sites distributed across the US Great Plains by making ca. bi-weekly measures during the growing seasons over three years. We quantified net methanotroph activity and diffusivity by using an approach combining a gas tracer, chamber headspace measurements, and a mathematical model. At each plot, we also measured environmental characteristics, including water-filled pore space (WFPS), soil temperature and inorganic nitrogen contents, and examined the relative importance of these for co..., ,